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2023-12-20

The applied free additional reinforcement is not considered in the punching shear design.

The applied free additional reinforcement (free rectangle, free circular, or free polygon) is not considered in the punching shear design or calculation.


Answer:

To avoid punching reinforcement, it may help to apply additional reinforcement in some areas. If the existing reinforcement in the punching shear area does not increase despite the reinforcement, the following problem is the cause:

  • The additional reinforcement requires the minimum dimensions or a required reinforcement length to be applied for the calculation.

It is calculated according to Section 6.4.4 / Equation 6.47 of EN 1992‑1‑1. In the example, this is shown for a rectangular column.
The basic reinforcement is 3.35 cm²/m, the additional reinforcement is also 3.35 cm²/m. If both reinforcements are effective, the result is a reinforcement of 6.7 cm²/m.

  • The program does not consider the required anchorage length of the additional reinforcement. It is necessary to adjust it manually.
  • In order to illustrate the problem, we calculate with a very fine mesh in the example. The required dimensions when entering additional reinforcements may increase if a very coarse mesh is set. Therefore, the required minimum length can then jump to the next mesh element here.

Author

Mr. Haase is responsible for development in the area of reinforced concrete structures, and provides technical support to our customers.



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